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<table width="100%" summary="page for ability.cov"><tr><td>ability.cov</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Ability and Intelligence Tests</h2>

<h3>Description</h3>

<p>Six tests were given to 112 individuals. The covariance matrix is
given in this object.
</p>


<h3>Usage</h3>

<pre>ability.cov</pre>


<h3>Details</h3>

<p>The tests are described as
</p>

<dl>
<dt>general:</dt><dd><p>a non-verbal measure of general intelligence using
Cattell's culture-fair test.</p>
</dd>
<dt>picture:</dt><dd><p>a picture-completion test</p>
</dd>
<dt>blocks:</dt><dd><p>block design</p>
</dd>
<dt>maze:</dt><dd><p>mazes</p>
</dd>
<dt>reading:</dt><dd><p>reading comprehension</p>
</dd>
<dt>vocab:</dt><dd><p>vocabulary</p>
</dd>
</dl>

<p>Bartholomew gives both covariance and correlation matrices,
but these are inconsistent.  Neither are in the original paper.
</p>


<h3>Source</h3>

<p>Bartholomew, D. J. (1987).
<em>Latent Variable Analysis and Factor Analysis</em>.
Griffin.
</p>
<p>Bartholomew, D. J. and Knott, M. (1990).
<em>Latent Variable Analysis and Factor Analysis</em>.
Second Edition, Arnold.
</p>


<h3>References</h3>

<p>Smith, G. A. and Stanley G. (1983).
Clocking <i>g</i>: relating intelligence and measures of timed
performance.
<em>Intelligence</em>, <b>7</b>, 353&ndash;368.
doi: <a href="http://doi.org/10.1016/0160-2896(83)90010-7">10.1016/0160-2896(83)90010-7</a>.
</p>


<h3>Examples</h3>

<pre>
require(stats)
(ability.FA &lt;- factanal(factors = 1, covmat = ability.cov))
update(ability.FA, factors = 2)
## The signs of factors and hence the signs of correlations are
## arbitrary with promax rotation.
update(ability.FA, factors = 2, rotation = "promax")
</pre>


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